add BS4 link

Author: okendoken

README.md

@@ -2,7 +2,7 @@ Awesome Bootstrap Checkbox
 ==========================
 [Font Awesome][] [Bootstrap][] Checkboxes & Radios plugin. Pure CSS way to make inputs look prettier. **No Javascript!**
 
-We have [new version][] with support [Bootstrap 4][].
+For **[Bootstrap 4][]** checkout [v1.0.0-alpha.1][] tag!
 
 **[Demo][]**
 
@@ -173,7 +173,7 @@ Based on the [Official Bootstrap Sass port][Bootstrap Sass] and the awesome [Fon
 [Demo]: http://flatlogic.github.io/awesome-bootstrap-checkbox/demo/
 [Bootstrap]: http://getbootstrap.com/
 [Bootstrap 4]: https://v4-alpha.getbootstrap.com/
-[new version]: https://github.com/flatlogic/awesome-bootstrap-checkbox/releases/tag/v1.0.0-alpha.1
+[v1.0.0-alpha.1]: https://github.com/flatlogic/awesome-bootstrap-checkbox/releases/tag/v1.0.0-alpha.1
 [Bootstrap Sass]: https://github.com/twbs/bootstrap-sass
 [Font Awesome]: https://github.com/FortAwesome/Font-Awesome
 [Glyphicons]: http://getbootstrap.com/components/#glyphicons